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The paper presents experimental data on the pesticides action (molinate (OrdramA), Dinitroortocresolum and chlorophos) at concentrations of 0.01 mg /l to 10 mg/l on sanitary-indicative (TBC, total coliform bacteria, E. coli, E. faecalis), potentially pathogenic ( Ps. aeruginosa) and pathogenic (S. Derby) microflora of the river water. As the test cultures there were used isolated from the reservoir and museum strains of microorganisms. Due to the fact that the rate of decomposition ofpesticides in water increases in direct proportion to the extent of its biological contamination, the experiments were performed with the river water: native and sterilized by autoclaving. There were identified species and strain differences in the microbial response to the action of pesticides. The selectivity of OrdramA action at a concentration of 0.1 to 10 mg/l on Salmonella and of chlorophos at a concentration of 10 mg/l for Salmonella and E. coli is manifested in the stimulation of the reproduction of these bacteria. Dinitroortocresolum in concentrations of 10 mg/l and 1 mg/l gives rise in the reproduction of Pseudomonas aeruginosa and inhibits the growth of total coliform bacteria and E. coli, in a concentration of 0.1 mg/l the preparation stimulates the viability of all the studied microorganisms. When entering the body of water, pesticides were found to cause changes of biocenosis in the river water and disturb bacterial self-cleaning processes. In conditions of pesticide pollution total coliform bacteria, E. coli and E. faecalis unable to maintain their indicative value and therefore the use of only them for the evaluation of the sanitary-epidemiological status of the water source appears to be insufficient. Due to the fact that the epidemic potential of water is directly dependent on quantitative content ofpathogenic and opportunistic pathogenic microorganisms in it, the reproduction Salmonella and Pseudomonas bacteria is a negative moment from the sanitary and epidemiological point of view.

There are considered special social and economic aspects of the epidemiology of Helicobacter pylori. These aspects acquired the particular importance for the last time due to the fact that the provision of the people with pure water has been becoming the focus of the attention of geopolitical and socio-economic interests in a number of countries. The availability ofpure drinking water serves a marker of the socio-economic state of the territory and the population living there. In Russia where different climatic conditions are deposited by considerable regional differences in the conditions of communal services caused both by various level of the socio-economic development of the territory, the supplementation with pure drinking water serves as the social determinant of the ecological conditions of the population’s life. This particularly has impact on the unfeasible technical state of the water distribution systems, microorganism ecology of which can substantially affect public health. The performed by authors a specialized screening ofpresented at the official web site of the joint-stock company «Mosvodokanal» current data concerning the quality of drinking water consumed by 2500 Moscovites, tested for the Helicobacter pylori infection revealed no deviations from the sanitary standards in the water received by the consumers. Along with that, the comparison of the map documents of the distribution of the Helicobacter pylori infection in Moscow with the distribution of citizens’ complaints of the decline of the quality of tap water has revealed a territorial fastening of the high values of the population infection rate of n^ylori and the urban sites with the greatest number of complaints. In the microbial ecology of water-distribution systems there are tightly aligned problems of their epidemiological safety, technical state and economic damage caused by corrosion as a result of microbiotic activity. In contrast to acute bacterial and viral infections which are deemed of the greatest importance when assessing the sanitary condition of water sources and water-distribution systems, the consequences of infection with H. pylori may not be manifestedfor a long time but some years later they may be manifested as serious chronic diseases (from gastritis to adenocarcinoma of the stomach and a wide range of extraintestinal pathologies), which causes great social and economic losses. Thus, the socio-economic aspect of the epidemiology of helicobacteriosis includes at least two components: the technic - the maintenance of the feasible technic and sanitary state of the water distribution systems and the medico-social - expenditures for screening and treatment of infected patients. In total they are an inseparable part of the prevention of socially-important diseases in the public health system.

The used methodology of the scientific substantiation of indicators is in the establishment of the conformity of laws of vital activity of indicator and pathogenic microorganisms in the real conditions of the action of the complex of factors, including disinfecting agents. In the one water sample simultaneously there were determined both the general indicator (GICB), thermotolerant (TTCB), glucose positive (GPCB) coliform bacteria, E.coli. On the base of long-term research in the various regions of the Russian Federation, as well with bearing in mind the analysis of domestic and foreign data, comparing the water quality and the incidence of intestinal infections in population it is recommended to use the index of determination of the total number glucose positive coliform bacteria (GPCB), which brings together a much broader range of bacteria of the Enterobacteriaceae family in comparison with total coliform bacteria (TCB) and thermotolerant coliform bacteria (TTCB) and warrants the absence in the test volume of water as an indicator lactose positive (E.coli, TCB, TTCB) and pathogens (salmonella) and potentially pathogenic bacteria which do not ferment lactose. Proposed index of GPCB is shown to allow to assess epidemiological risks not only more accurate, but also more efficiently without increasing the cost performance of bacteriological research.

The aim is the study of the circulation, biological activity, persistent potential and genotypic characteristics of opportunistic Enterobacteriaceae of microbial community of the Lena River which is the one of the largest sources of water in Russia and Siberia. Gram-negative component of microbial community in the Lena River was mainly represented by Enterobacteriaceae (80%), including dominated Escherichia (dominant class) and Enterobacter and Klebsiella (subdominant class). In conditions of anthropogenic pollution there is a reorganization of microbial community of the Lena River in the direction of the increase in the proportion of opportunistic pathogens, their species diversity; there is a change of the biological activity of microorganisms, gains of share of strains characterized by antilysozyme activity, hemolytic activity, production DNase, phosphatase. The parameters of system “lysozyme-antilysozyme” are changing, the frequency of the occurrence of bacteria with antilysozyme activity is increasing. This shows the restructurization of the microbial community of water objects. Microorganisms of water objects in territories of anthropogenic pollution are characterized by multiple antibiotic resistance. The proportion of gram-negative opportunistic Enterobacteriaceae in microbial communities of water ecosystems determines the potential danger of water objects and the impact on the level of antibiotic resistance of bacteria. Opportunistic Enterobacteriaceae of microbial community of the Lena River near the city of Yakutsk are characterized by the presence of genetic determinants of pathogenicity (hlyA and sfaG). This is indicative of their potential epidemiological relevance. Microorganisms with high biological activity are markers of their epidemiological danger.

The increasing chemicalization of production and life leads to the pollution of water bodies by chemicals, the effect of which on the micro - and macro - organisms is poorly understood. This section of the study in sanitary bacteriology is becoming ever more topical and is an important task of modern hygienic science. One of complicacies of the study of the problem is related with the fact that the presence of only experimental data fails to be sufficient, as the impact of any given chemical substance on different bacteria in the experiment does not mean that under natural conditions, similar results will be obtained. One reason for this may be the inhibitory effect of the given chemical on biological properties of bacteria, while in field conditions in the water several chemicals interacting with each other can exist. In this regard, the aim of the work was to assess the indicator value of sanitary and microbiological indices of epidemic hazard of water use in conditions of chemical pollution of surface water bodies.

The wide circulation of Klebsiella bacteria in water ofwater objects of different climatic zones of Russia and various function is established. So bacteria of the Klebsiella strain are in superficial sources of the centralized water supply depending on extent of their biological and chemical pollution; underground waters at the unprotected water-bearing horizons; in drinking water at insufficiently effective system of its cleaning and disinfecting. Klebsiella circulating in water was shown to keep properties of pathogenicity and a virulence, possess resistance both to modern preparations and disinfecting agents (chlorine, an ultraviolet to radiation). Bacteria of the Klebsiella strain have high penetration in the water-bearing horizons. At strains of Klebsiella there is allocated considerable pathogenic potential (adhesive, invasive, phosphatase, lecithinase, DNA-ase, hemolytic activity) and genetic markers of pathogenicity of cnf-1. The etiologic role of bacteria of Klebsiella and an infecting (100, COE/dm3) dose emergence of acute intestinal infections (AII) is established. Detection of Klebsiella in water objects and especially in water of drinking appointment, in the absence of total coliform bacteria (TCB) contributes to the epidemic danger of water use.

In the article there are presented the results of a study of halotolerance of enterobacteria isolated from water and fish in the Volga River delta, which were dominant in the microbial landscape of these biotopes. Their halotolerance was studied by means of inoculation of daily pure cultures of meat--peptone broth with 3, 7 and 10% of sodium chloride and incubation at 37°C. At that all studied microflora was found to have significant indices of halotolerance with a predominance of aquatic isolates. At that in 3,0 and 7,0 % NaCl concentrations were very similar, but in 10% NaCl broth the halotolerance of water strain was almost 2.0 times higher than the in fish ones. Among isolated Enterobacteriaceae most halophilic bacteria were from the Proteus group, Citrobacteria and Enterobacteria. The halotolerance of isolated enterobacteria in hydroecosystem of the Volga River delta had seasonal specificity and dynamics. There was established the dynamic growth of this sign in the water and fish strains from spring to autumn. Thus, the analysis of the obtained results of the long-term conducted study has shown the wide dissemination of conditionally pathogenic enterobacteria in water and fish, and their high halotolerance and the ability of some of them to remain viable up to salt production. It gives grounds to recommend the necessity of the introduction of them into the normative documentation in the implementation ofthe sanitary-microbiological control of not only raw materials but also ready salted fish production.

The present study is devoted to theoretical questions of optimization of integrated assessment of the composition and properties of drinking water with the use of the Water Quality Index (WQI) and considering in it all 4 criteria for its hygienic quality-sanitary-toxicological, microbiological, radiation and organoleptic. There is presented a sequence of the analysis of benchmark data of the laboratory study of drinking water, including the selection of priority indices, their distribution into 4 groups according to hygienic criteria, calculations the ratios of real values (C) of indices to their hygiene MPC and the final calculation of the WQI. There is emphasized the importance of classes of hazard of substances, and the need for the special attention to the substances-carcinogens in the integrated assessment of water quality. To overcome the non-equivalence of contributions to the assessment of water quality factors, measured in different units, often disparated in their effect on human health, there are used the principles of combined action at levels below the MCL:C/MPC indices of performance of the unidirectional action are summed (e.g. carcinogenic substances), from indices of the independent action there are selected the most significant ones with the highest values of C/MPC, besides that there are also used counterbalancing factors K determined accordingly to Delphi method, with a maximum values of 5 for carcinogens and the minimum value of 1 for the substances affecting the organoleptic properties ofwater. There is presented the scheme of the final calculation of the value of WQI.

There are considered the issues related to the possibility to rate of Helicobacter pylori (H. pylori) content in drinking water. There is described the mechanism of of biofilm formation. The description refers to the biofilm formation mechanism in water supply systems and the existence of H. pylori in those systems. The objective premises of the definition of H. pylori as a potential limiting factor for assessing the quality of drinking water have been validated as follows: H. pylori is an etiologic factor associated to the development of chronic antral gastritis, gastric ulcer and duodenal ulcer, and gastric cancer either, in the Russian population the rate of infection with H. pylori falls within range of 56 - 90%, water supply pathway now can be considered as a source of infection of the population with H. pylori, the existence of WHO regulatory documents considering H. pylori as a candidate for standardization of the quality of the drinking water quite common occurrence of biocorrosion, the reduction of sanitary water network reliability, that creates the possibility of concentrating H. pylori in some areas of the water system and its delivery to the consumer of drinking water, and causes the necessity of the prevention of H. pylori-associated gastric pathology of the population. A comprehensive and harmonized approach to H. pylori is required to consider it as a candidate to its rating in drinking water. Bearing in mind the large economic losses due to, on the one hand, the prevalence of disease caused by H. pylori, and, on the other hand, the biocorrosion of water supply system, the problem is both relevant in terms of communal hygiene and economy.

Criterion of the epidemic safety of drinking water is the absence of pathogenic and potentially pathogenic microorganisms. Currently, water quality control is performed in terms of the index of total coliform bacteria (TCB). TCB index oriented to the labile lactose sign has not sufficient relevance in the determination of the degree of the epidemic danger in the water use in relation to Salmonella and potentially pathogenic microorganisms. The frequency of detection of GCB in standard quality of drinking water as well as the application of the methodology for the assessment of the microbial risk of the occurrence of bacterial intestinal infections with the use of integral index--GCB, provide the most reliable prediction of risk in the occurrence of water-caused intestinal infections and more objectively reflect the epidemiological importance of drinking water in their distribution among the population. Proceeding from the data obtained, it is advisable to carry out the quality control of drinking water with the use of the broader indicator index GCB- detected from basic signs of the Enterobacteriaceae family--glucose fermentation and oxidase test and oxidase test.

For the purpose of harmonization of microbiological and parasitological indices and benchmarks there was performed the comparative analysis of the requirements for the quality of drinking water in respect of the epidemic safety on the basic regulations of Russia, the Directive Council of the European Union EU, WHO, the United States, Canada, Australia, Finland, Sweden, Brazil, France, Japan and China. As a result, there were revealed the priority bacteriological, virological and parasitological parameters: E. coli--indicator of recent fecal contamination, coliforms, heterotrophic bacteria colony count (Heterotrophic plate count), which is in the water legislation of the Russian Federation is characterized as total bacterial count (TBC), being an integral index of the quality of wastewater treatment technologies and hygienic condition of the water supply systems, coliphages as an indicator of viral contamination. In the Guidelines for drinking-water quality control, WHO and a set of countries there is recommended a more wide range of indicators: enterococci, Clostridium perfringens, Pseudomonas aeruginosa, enteroviruses, parasitological indices. With aim of harmonization of the requirements for the quality of drinking water in the Russian Federation with international approaches to the revision of the Sanitary Regulations and Norms (SanPin) 2.1.4.1074 into the project there are introduced priority indicator parameters of bacterial, viral and parasitic contamination of water, evidence-based guidelines.

The analysis of literature data was carried out and performed research justifying the epidemic value of detection in water P. aeruginosa in drinking and domestic water use. The were revealed features of the vital activity of P aeruginosa in water bodies as opposed to conventional microbiological indicators. It was shown that the coliform group indices can not guarantee the epidemic safety of drinking water use in relation to P aeruginosa. The data obtained justify the need for the introduction of P aeruginosa as an additional index in monitoring the water quality of centralized and decentralized water supply.

The question of need for standardization and validation of the complex methods to establish the maximum concentration limit (MCL) ofbiotechnological strains in the water of water bodies is under discussion. On the basis of the experimental studies it has been shown that a unified quantitative criterion for safety could not to be recommended for biotechnological strains and therefore requires the study of each strain in order to substantiate the safe level in water of water bodies. Proposed biosafety program should include the study of pathogenic properties in acute experiments and specific effects in subchronic experiments to study the influence of strains on the process of water purification and a risk assessment of transformation products of chemicals and the justification of the safety factor when establishing MCL t in terms of the toxic effect.

Due to intensive anthropogenic pollution of water environment generally accepted indicators of epidemic security of water bodies - common bacteria and thermotolerant coliform bacteria do not always permit to obtain an objective characterization of bacterial contamination of tap water. From the point of view of authors the integral index - glucose positive coliform bacteria most adequately reflect the sanitary-hygienic and epidemiological situation of water bodies. In monitoring for bacterial quality of tap water it is advisable to determine glucose positive coliform bacteria, that will provide the relevance of estimation of the epidemiological safety of water use. According to the method developed by the authors the calculation of the index of population risk of acute intestinal infections occurrence in dependence on the quality of tap water in Azov and Tsimlyansk towns.

The possibility of using 12 heterogeneous sensitizers (HS) based on phthalocyanines covalently grafted to aminopropyl silicagel for disinfection of water from bacteria has been studied. For reliable water quality control the technique of performing bacteriological analysis in the presence of HS beads in the sample has been elaborated. The conditions increasing the efficiency of photo disinfection in the presence of HS were studied. Algorithm for estimation of photo disinfectant effect of HS against bacteria was substantiated. Obtained data confirm the perspective of further studies on the substantiation of the possibility of the application of HS for water disinfection.

Water samples and surface swabs from 15 Moscow public indoor swimming pools (SP), where disinfection was carried with the use of chlorine reagents, were studied and excess of bacteriological indicators standards was revealed, infestants of fungous skin and nails diseases were allocated. The research results showed both the absence of epidemic significant information value of bacteriological indicators in relation to infestants of fungous diseases and discrepancy of efficiency of existing recommendations for disinfection actions to requirements on providing sanitary-and-epidemiologic safety of SP visitors.

The paper reviews the literature on the current hygienic problems of centralized hot water supply for the population. It gives data on the types of domestic hot water used by the population in quantities and at temperatures. The paper considers the importance of meeting the standards for the temperature of hot water at the points of water pumping to prevent legionellosis and other diseases associated with the opportunistic microflora being in hot water. The possible negative effect of chlorinated water disinfection byproducts, present in hot water on the population's health is considered in detail.

The survival rate of bacteria of the genera Pseudomonas and Enterococcus isolated from Baikal Lake, exposed to different concentration of calcium hypochlorite used as a main agent for drinking water disinfection, was studied. Experimental studies have shown that chlorination was imperfect as this method is not always effective against Enterococci.

The authors propose a new heterogeneous photo sensitizer containing aluminum tetrakis [bis(cholinyl)phenylthio)] phthalocyanine grafted onto silica as an active phase. A poliovirus type 1 LSc2ab and RNA-containing phage MS2 model was used to show that the sensitizer had photo decontaminating activity against viruses and may be used to purify water from viral contamination. The mechanism for removal of viruses from water is two-step and involves the adsorption of the virus on the heterogeneous sensitizer particles and the photodynamic inactivation of the adsorbed virus.

The paper reviews the data characterizing the routes of transmission of Helicobacter pylori. Particular emphasis is laid on the water transmission route that has not been long considered to be important despite strong epidemiological evidence that allows it to be regarded as one of the most important routes of transmission of this infection. It describes the most favorable conditions for this microorganism to survive in the water systems, including plumbing, and a possible survival mechanism via biofilm formation and zooplankton symbiosis. The pathogen is able to bind to autochronous microorganisms in the biofilms and to generate itself the latter. It is not inconceivable that this microbe can persist and even multiply within protozoa. Due to the improved analytical studies, there are additional possibilities to detect new pathogenic microorganisms that have not been historically regarded as pollutants. These microorganisms are of interest to community hygiene specialists. The preferred routes of urban and rural transmission of the pathogen may be different, which should be taken into account when elaborating preventive measures.

The authors have investigated the adsorption-elution of intestinal bacteriophages T2 and MS2 as a model of enteric viruses, by using the coagulants aluminum oxychloride (AOX78) and aluminum sulfate (AS). The investigation has ascertained the effective removal of the phages from water with AOX78 (98.7-100%) and the low efficiency of elution of coliphages from the particles of AOX hydrolysis products (0.1-3.7% of the baseline count of bacteriophages), which may suggest that AOX has antiviral activity. The above phenomena produced by AS are less evident.

The paper presents experimental data on the effect of different concentrations of the salts of cadmium, copper, and zinc on the adaptive potentialities of the most common opportunistic microflora in the Volga-Caspian region. The findings suggest that natural microorganisms (Aeromonas and Citrobacter) show a high metal resistance that seems to be associated with steadily increased background levels of these metals in the waters of the Volga-Caspian basin.

The paper gives data on the use of techniques to detect and register Salmonella in the water objects, by applying a new liquid nutrient medium. Experimental and field studies have shown its advantage over the accumulation media widely used in practical healthcare. It has been ascertained that the nutrient medium not only accumulates biomass, but also provides the restoration of the biological properties of uncultivated Salmonella species. The use of the nutrient medium at practical laboratories makes it possible to unify guidelines for the examination of water objects with varying degrees of biological pollution and to obtain the comparable results of analyses.

The paper gives the data characterizing the specific features of formation of an anthropogenic load on water bodies in north regions; sanitary and hygienic criteria for estimating the biological contamination; and the factors that increase the biological productivity of the algal flora; a classification of eutrophic waters is also proposed.

To supply the population with qualitative potable water is a priority problem in the provision of sanitary-and-epidemiologic well-being and in the prevention of disease in the Vologda Region. The monitoring of the results of laboratory control over the quality of drinking-water and the assessment of health risk enabled a package of measures to be proposed to optimize the conditions of drinking water supply in the Vologda Region. The risk assessment technology used by a state agency for sanitary-and-epidemiological surveillance makes it possible to substantiate a system of actions to organize household water use and to include scientifically grounded proposals into the developed regional and local programs.

Due to the fact that swimming pools are widely used as sports and fitness objects and that their construction is growing in the public and individual sectors, there is an increasing need for more effective sanitary and microbiological monitoring of the epidemic safety of bathers against not only enteral infections, but also infectious diseases of the skin, mucosae, and nail plates, including onychomycosis. The data available in the literature and the authors' findings indicate that swimming pool attendance might be a reason for the spread of mycosis pathogens and necessitates the development of standards for these indicators and a search for novel promising disinfectants.

The pattern of the negative effect of biotechnological strains belonging to different taxons was experimentally studied. The effect of the strains manifested as imbalance of immunocompetent cells, development of immediate and delayed hypersensitivity, and altered qualitative and quantitative characteristics of the autochtonic microflora of the intestine. The minimum acting (10(5) cells/l) and non-acting (10(4) cells/l) enteral exposure levels were determined for the bulk of the test strains. Analysis of the authors' findings and the data available in the literature made it possible to propose a study program on the hygienic regulation and standardization of industrial microorganisms and their based microbiological products in the reservoir water.

Variability in the cultural and biochemical properties of indicator, opportunistic, and pathogenic bacteria and possibilities of their reactivation after exposure to chlorine-containing reagents and during photo-activated disinfection processes in the presence of photosensitizes were experimentally studied to enhance the epidemic reliability and adequacy of microbiological monitoring in the evaluation of the decontamination efficiency of water of its various use types. Reactivation of coliform bacteria, enterococci, salmonellas, and the total number of microbes were estimated after exposure to the bacteriostatic doses of sodium hypochlorite and chlorine dioxide when the river and waste waters were decontaminated. During photo-activated disinfection under the action of the photosensitizers methylene blue and proflavin acetate given in the bacteriostatic doses, there was transition into the uncultivated state, followed by 1-5-day reactivation of both museum strains and strains isolated from waste waters, such as Salmonella infantis spp, Salmonella enteritidis spp, Salmonella enteritidis 5765 ATCC, Pseudomonas aeruginosa 10145, Pseudomonas aeruginosa spp, Escherichia coli 1257, Staphylococcus aureus 906, and Enterococcus faecalis 29212. Moreover, Pseudomonas and Salmonellas not only regained their viability, but also multiplied up to the control level. Recommendations are given how to improve methods for monitoring the efficiency of disinfection, by taking into account a possible variability in the cultural and biochemical properties of bacteria and for reactivation by monitoring the trend in the process during 5 days.

The authors describe their developed methodology to draw up lists for drinking water quality control on the whole territory of the Russian Federation and at specific waterworks of its subjects. The paper considers a 4-step scheme for applying the methodology and a possibility of its use to add and shorten the lists, by keeping in mind the local sanitary situation. The proposed scheme for listing the priority substances and indicators may be regarded as the optimal solution for equalization of mutually exclusive trends in the quality control of drinking water by a sanitary service and water canals and ensures its safety to human health, reasonably focusing attention only on the minimum of actually priority substances that are individual to each water supply system.

In the past 2 years, the malaria epidemiological situation has drastically improved in Moscow: only sporadic cases of local transmission of tertian (Plasmodium vivax) malaria have been notified, which sets a task to eradicate malaria in the megalopolis in 2010. In this connection, the surveillance of the malaria vectors Anopheles mosquitoes is assuming prime importance. The results of entomological monitoring have shown its efficiency on the territory of the megalopolis. Main efforts have been directed to the application of safe controlling methods against the mosquitoes and to hydraulic engineering actions to reduce "area susceptibility". Entomological observations have demonstrated benefits from the correctly chosen and constantly performed hydraulic engineering measures that guarantee a long-term and positive impact on the malaria situation.

The paper outlines materials on how to improve a method for indication of water viral pollution in different water objects of the environment, by applying a MFM filtration module based on tangentially radial-mode water microfiltration and viral concentration on the positively charged membranes, by using the secondary stage of concentration. Experimental and full-scale studies have demonstrated that this method for virus isolation has a high effectiveness and is based on the employment of the materials made in Russia. This determines its rapid introduction into the system for the sanitary-virological monitoring of practical laboratories of various departments, which will favor the higher efficiency of epidemiological surveillance as an integral part of nonspecific prophylactic measures of virus infections of water etiology.

The paper gives many years' data on the size of the opportunistic and sanitary-significant microflora of pike perches (Stizostedion) and water in the producer's food fish areas of the Volga river estuary, as well as the results of ecological and microbiological studies of the water from the above areas, which include the determination of the total amount of the bacterial plankton on membrane filters, the number of heterotrophic bacteria, which has provided an assessment of the habitat quality of hydrocoles in accordance with the complex ecological classification of the quality of the land's surface water. The paper analyzes the seasonal abundance and spatial distribution of the most common opportunistic microorganisms, as well as the markers of their pathogenicity.

The present-day sanitary state of most sea beaches within the precincts of Vladivostok is mainly determined by the fact that pollutants along with household and industrial sewerage flows are carried away into the beaches without proper treatment. A multitude of the pathogenic and opportunistic flora with fecal sewerage flows enters the coastal zone. In summer holiday months (July and August), beach-front areas of the city are polluted with organic substances, i.e. they are characterized as polysaprobic, which creates conditions for the multiplication of pathogenic microorganisms. In terms of sanitary and microbiological indices, the surface waters in the city's recreational zones are characterized by persistent fecal pollution that greatly exceeds the sanitary standards, abundant enterobacteria, including epidemiologically potentially dangerous species.

Summary. The paper provides comparative characteristics of water quality in the assessment of a risk for intestinal infections in drinking water use. It has shown that of the greatest predictive value is direct detection of potentially pathogenic microorganisms, as well as the integral indicator determined by glucose fermentation, such as glucose-positive coliform bacteria. Estimation of the per cent of nonstandard samples of water before its entering the distribution network and in the latter, including glucose-positive Escherichia coli GPEC, is recommended. The samples containing GPEC in a quantity of more than 2 CFU/100 ml should be singly taken into account.

The paper deals with the important urgent problem in the provision of epidemiological drinking water. It considers the chemical, biological, toxicological, technological, environmental, and economic aspects of the use of chlorine dioxide as a highly effective disinfecting and oxidizing agent in water purification and decontamination processes. The authors present the results of their own studies. They conclude that chlorine dioxide is an epidemiologically, ecologically, and toxicologically safe and technologically adequate and economically acceptable agent for water treatment in the domestic water supply systems of localities.

The paper presents materials to provide a scientific rationale for the microbiological parameters enhancing the efficiency of drinking water quality control from the point of view of reliability in the provision of epidemic water consumption safety (coliform bacteria being identified by the glucose index; E. coli). Based on the criterion assessment of the significance of microbial water contamination in relation to morbidity rates, the authors have been developed bacteriological standards--the absence of microorganisms in a 300-ml water sample. Evidence is provided for the epidemically significant level--more than 2 CFU of coliform bacteria in 100 ml. A rapid determination procedure has been substantiated in the experimental studies of the effects of oxidase reagents on the viability and biochemical properties of E. coli bacteria. In search for current technologies for membrane filtration, experimental rationale has been made for the possibility of using track membranes for sanitary and bacteriological water analyses.

Quantitative relationships were studied between the indicators (common coliform bacteria (CCP), glucose-positive bacteria (GPB), thermoduric bacteria (TDB), coliform bacteria, enterococci, clostridia, coliphages) and the opportunistic (Pseudomonas aeruginosa, Proteus, Klebsiella) and pathogenetic (Salmonella and intestinal viruses) microorganisms at the stages of effluent purification and decontamination, in processes of self-purification in the water reservoirs and of water preparation at water-supplying stations, as well as in the association with the incidence of acute intestinal infections of bacterial and viral genesis in different climatic zones of the country. Salmonella and the opportunistic bacteria of the Enterobacteriaceae family and Pseudomonas aeruginosa were found to be highly resistant to detoxifying agents and environmental factors, adaptable, able to reproduce in pure water, to long survive in underground waters, and to accumulate when water is desalinated at the erections. The cases of intestinal infections were found in the population using the portable water of the standard quality in terms of E. coli, TDB, CCB, and enterococci. In this case only the wider integral index of GPB, which includes the indices of E. coli, TDB, CCB, as well as lactose-negative pathogenic and opportunistic species retains its sanitary significance in terms of all signs and is a reliable indicator of the potential epidemic hazard of drinking water use. Long-term studies have provided evidence for the sanitary value of coliphages as indicators of viral drinking water contamination.

The paper considers unfavorable consequences of the use of biotesting to define the conditions of effluent discharge into water objects. Evaluation of discharge hazard by the index "no toxicity" in the biological tests has been shown to allow both safe 100-1000-fold excesses of hygienic MAC in water; routine short-term experiments on biotest objects are not informative as to the substances that have carcinogenic and other long-term and specific effects; biotesting cannot replace the existing state system of sanitary standards and regulations which remain the basis of the population's health care in the field of water hygiene and sanitary protection of water reservoirs.

Water of Odessa Bay is polluted by drainage waters which contain coliform bacteria. Sometimes bacterial quantity was more than it is permitted by standards for sea waters. In can have unfavorable influence on sea water in recreational facilities.